1. Field of the Invention
The present invention relates to securing of heat sinks to electronic devices, and particularly to clips of heat sink clip assemblies that have coiled structures which can be configured to provide suitable pressing force acting on a heat sink.
2. Related Art
Advances in microelectronics technology have resulted in electronic devices which process signals and data at unprecedented high speeds. During operation of many contemporary electronic devices such as central processing units (CPUs), large amounts of heat are produced. The heat must be efficiently removed, to prevent the system from becoming unstable or being damaged. Heat sink assemblies are frequently used to dissipate heat from these electronic devices.
A clip is often used to attach a heat sink to an electronic device. An example of a conventional heat sink clip assembly is disclosed in Taiwan Patent Application No. 86212202. In such assembly, a pressing wire attaches a heat sink to an electronic device. A pair of coiled portions is formed at opposite ends of the pressing wire. A fastener extends across a corresponding coiled portion and engages with a through hole of a motherboard, thereby attaching the heat sink to the electronic device. However, the heat sink clip assembly cannot keep the heat sink in position efficiently. The pressing wire occupies space between fins of the heat sink, and limits a density of fins of the heat sink. This reduces an effective heat-dissipating area of the heat sink. Further examples of conventional heat sink clip assemblies are found in U.S. Pat. Nos. 5,684,676 and 5,730,210.
An improved heat sink clip assembly which overcomes the above-mentioned problems is desired.
Accordingly, an object of the present invention is to provide a heat sink clip assembly having coiled structures which can readily and securely attach a heat sink to an electronic device.
Another object of the present invention is to provide a heat sink clip assembly which has a simple structure and reduces costs.
To achieve the above-mentioned objects, a heat sink clip assembly of the present invention is used to attach a heat sink to a CPU which is mounted to a motherboard. The heat sink clip assembly comprises a pair bolts, and two wire clips. Two screw holes are defined in opposite side faces of the heat sink. Each bolt comprises a pole, a head, and a threaded end. Each wire clip has a coiled portion, and two spring arms respectively extending from opposite ends of the coiled portion. The coiled portions of the wire clips are respectively placed over the poles of the bolts. The threaded ends of the bolts are screwed into the screw holes of the heat sink; thus, each wire clip is retained between the head of a corresponding bolt and a side face of the heat sink. A hook is formed at a distal end of each spring arm, for engaging in a corresponding through hole of the motherboard.